文章目录
- 41 嵌套的for循环
- 42 for循环嵌套练习(1)
- 43 for循环嵌套练习(2)
- 44 break和continue
- 45 质数练习补充
41 嵌套的for循环
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset = "utf-8">
<script type="text/javascript">for(var i = 0; i < 5; i++){for(var j = 0; j < 5; j++){document.write("* ");}document.write("<br>");}for(var i = 1; i <= 5; i++){for(var j = 1; j <= i; j++){document.write("* ");}document.write("<br>");}for(var i = 5; i >= 1; i--){for(var j = 1; j <= i; j++){document.write("* ");}document.write("<br>");}</script>
<style>
</style>
</head>
<body>
</body>
</html>
42 for循环嵌套练习(1)
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset = "utf-8">
<script type="text/javascript">for(var i = 1; i <= 9; i++){for(var j = 1; j <= i; j++){document.write("<span>" + j + "*" + i + "=" + (j * i) + "</span>" );}document.write("<br>");}
</script>
<style>body {width: 2000px;}span {display: inline-block;width: 80px;}
</style>
</head>
<body>
</body>
</html>
43 for循环嵌套练习(2)
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset = "utf-8">
<script type="text/javascript">for(var i = 2; i <= 100; i++){var flag = 1;for(var j = 2; j <= parseInt(i ** 0.5); j++){if(i % j == 0){flag = 0;break;}}if(flag){document.write(i + " ");}}
</script>
<style>
</style>
</head>
<body>
</body>
</html>
44 break和continue
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset = "utf-8">
<script type="text/javascript">for(var i = 0; i < 5; i++){console.log(i);break;}if(true){break;console.log(i);}outer:for(var i = 0; i < 5; i++){console.log("外层循环");for(var j = 0; j < 5; j++){break outer;console.log("内层循环"); }}for(var i = 0; i < 5; i++){console.log(i);if(i == 2){continue;}}console.time("test");for(var i = 0; i < 1000000; i++){for(var j = 0; j < i; j++){}}console.timeEnd("test");
</script>
<style>
</style>
</head>
<body>
</body>
</html>
45 质数练习补充
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset = "utf-8">
<script type="text/javascript">for(var i = 2; i <= 100; i++){var flag = 1;for(var j = 2; j <= Math.sqrt(i); j++){if(i % j == 0){flag = 0;break;}}if(flag){document.write(i + " ");}}var result = Math,sqrt(4);
</script>
<style>
</style>
</head>
<body>
</body>
</html>
